View Compilation Error

0_0_14750145_29530.cpp: In function 'bool solve()':
0_0_14750145_29530.cpp:5:22: error: 'sscanf' was not declared in this scope
 if(sscanf(s, "%d", &c) != 1) return 0;
                      ^
0_0_14750145_29530.cpp:6:19: error: 'sprintf' was not declared in this scope
 sprintf(t, "%d", c);
                   ^
0_0_14750145_29530.cpp:7:15: error: 'strcmp' was not declared in this scope
 if(strcmp(s, t) != 0) return 0;
               ^
0_0_14750145_29530.cpp: In function 'int main()':
0_0_14750145_29530.cpp:12:13: error: 'gets' was not declared in this scope
 while(gets(s)){
             ^
0_0_14750145_29530.cpp:13:21: error: 'scanf' was not declared in this scope
 scanf("%d%d", &a, &b);
                     ^
0_0_14750145_29530.cpp:14:9: error: 'getchar' was not declared in this scope
 getchar();
         ^
0_0_14750145_29530.cpp:16:24: error: 'puts' was not declared in this scope
 puts(ans ? "YES" : "NO");
                        ^